Data Sheet
Pico TLynxTM 6A: Non-isolated DC-DC Power Modules
January 13, 2011
2.4 – 5.5Vdc input; 0.6Vdc to 3.63Vdc output; 6A output current
modules or tied to VIN for positive logic modules) so that
the module is ON by default. After applying input
Vo
voltage to the module, a minimum 10msec delay is
required before applying voltage on the SEQ pin. This
delay gives the module enough time to complete its
internal power-up soft-start cycle. During the delay time,
the SEQ pin should be held close to ground (nominally
50mV ± 20 mV). This is required to keep the internal op-
amp out of saturation thus preventing output overshoot
during the start of the sequencing ramp. By selecting
resistor R1 (see fig. 43) according to the following
equation
Rmargin-down
MODULE
Q2
Trim
Rmargin-up
Rtrim
24950
R1 =
ohms,
VIN − 0.05
Q1
the voltage at the sequencing pin will be 50mV when
the sequencing signal is at zero.
GND
Figure 42. Circuit Configuration for margining
Output voltage.
MODULE
VIN+
Monotonic Start-up and Shutdown
The Pico TLynxTM 6A modules have monotonic start-up
and shutdown behavior for any combination of rated
input voltage, output current and operating temperature
range.
499K
+
OUT
R1
Startup into Pre-biased Output
-
SEQ
10K
The 5.5V Pico TLynxTM 6A modules can start into a
prebiased output as long as the prebias voltage is 0.5V
less than the set output voltage. Note that prebias
operation is not supported when output voltage
sequencing is used.
GND
Figure 43. Circuit showing connection of the
sequencing signal to the SEQ pin.
Output Voltage Sequencing
After the 10msec delay, an analog voltage is applied to
the SEQ pin and the output voltage of the module will
track this voltage on a one-to-one volt bases until the
output reaches the set-point voltage. To initiate
simultaneous shutdown of the modules, the SEQ pin
voltage is lowered in a controlled manner. The output
voltage of the modules tracks the voltages below their
set-point voltages on a one-to-one basis. A valid input
voltage must be maintained until the tracking and output
voltages reach ground potential.
The APTH006A0X modules include a sequencing
feature, EZ-SEQUENCE that enables users to
implement various types of output voltage sequencing in
their applications. This is accomplished via an
additional sequencing pin. When not using the
sequencing feature, either tie the SEQ pin to VIN or
leave it unconnected.
When an analog voltage is applied to the SEQ pin, the
output voltage tracks this voltage until the output
reaches the set-point voltage. The final value of the
SEQ voltage must be set higher than the set-point
voltage of the module. The output voltage follows the
voltage on the SEQ pin on a one-to-one volt basis. By
connecting the SEQ pins of multiple modules together,
all modules can track their output voltages to the
voltage applied on the SEQ pin.
When using the EZ-SEQUENCETM feature to control
start-up of the module, pre-bias immunity during start-up
is disabled. The pre-bias immunity feature of the
module relies on the module being in the diode-mode
during start-up. When using the EZ-SEQUENCETM
feature, modules goes through an internal set-up time of
10msec, and will be in synchronous rectification mode
when the voltage at the SEQ pin is applied. This will
result in the module sinking current if a pre-bias voltage
is present at the output of the module. When pre-bias
immunity during start-up is required, the EZ-
For proper voltage sequencing, first, input voltage is
applied to the module. The On/Off pin of the module is
left unconnected (or tied to GND for negative logic
LINEAGE POWER
15
LINEAGEPOWER [ LINEAGE POWER CORPORATION ]
